i fail at keeping corys...

This is a discussion on i fail at keeping corys... within the Catfish forums, part of the Freshwater and Tropical Fish category; -->
Originally Posted by marshallsea
IMO, I think the boiling is too kill any living thing in or on the wood. However, there may be ...

IMO, I think the boiling is too kill any living thing in or on the wood. However, there may be metals or minerals in the wood that can cause problems, that boiling may not remove. Just a thought, I could be wrong. P.S. What were the signs of flukes that you saw?

scratching gills on things, really fast breathing, general weakness and disorientation...also more freqent going up to the surface for airl, I think.

How long after you bought your cories did they get sick? Sometimes "perfectly healthy" fish bought aren't perfectly healthy after all. Also, how many did you buy?

The first time I think I got three or four (the pandas); can't remember how many peppereds, but probably a similar number. I can't remember exactly how long it was before they started to seem ill, but not very long, probably only a few days?
It's worth noting that when I first got the pandas I was in the process of setting up a new tank (which wasn't yet cycled, so I'm sure that didn't help!) and at first they were kept in a much smaller (6 gallon) tank while I waited for the new tank to settle down. They only started to show signs of illness once I added them to the new tank. But the peppered corys were added much more recently when the tank was cycled, and they got sick too...

Sorry to hear you are having so many problems keeping corys. From the information given, I would think the issue is with the amount of nitrogen compounds (Ammonia or Nitrate) in your tank. Try taking it to a LFS to see if they will test Ammonia, Nitrate, pH and your hardness (KH and GH). It behooves a store to test your water for free. These other water characteristics are good to know but are likely not the problem because of the wide range of conditions that Corys can be kept.

The visible detritus is what I am keying on as the issue. When you do a water change, you need to remove the debris or you could have a build up of ammonia or nitrate. Ammonia is far more toxic and when it is present in a just a small amount it can stress a fish leaving it susceptible to disease or kill the fish in a short period of time. Nitrate will also stress and kill fish but it take much higher levels.

I think some people get stuck on the idea that they are doing a certain percent water change and do not think about what they are trying to accomplish with the water change. Ilook at it as...

Over a period of time, the amount of Nitrogen (ammonia and or nitrate) removed needs to be greater than or equal to the amount of Nitrogen introduced to the aquarium and the more frequent the water change the smaller the spike of Nitrogen compounds.

I have a pH test kit and regularly test the pH, although I don't have a kH or ammonia/nitrite/nitrate test kit. The pH seems to stay constant at a slightly acid pH. I did buy one of those dip-strips for testing ammonia etc. and although I know they're famously inaccurate, it showed zero of any of those toxins when I tested the water! I asked people on here about this and they thought it was possibly due to the large number of plants (and algae!) in my tank using up all the nitrate.

I definitely need to get a gravel vacuum, or make one, to clean properly.

Corys are portrayed as hearty fish in many circles and they are given the proper conditions. My experience has been that they are very sensitive to change in water parameters. After having very mixed results, I have discovered that doing a 50% water change right before adding them to the tank has worked like a charm.

thanks for the tip, I'll give it a try if I ever get corys again. Yes, they do seem to be very sensitive to anything being slightly wrong in their environment. But what I don't understand is how the pair of peppered corys I had all those years ago managed to live for three years or so without ever getting seriously sick. I transferred them from different tanks constantly, so they had to experience the whole cycling thing multiple times, put up with all kinds of tankmates and water parameters, and most of the tanks I kept them in were much too small, as well! Plus they were the only fish that survived a disaster where a filter that had been turned off for a week blasted toxic goop into the tank (stuff had been rotting in it, ew!).
I can't reconcile that with my experience of keeping corys ever since then...

A revelation! thanks for telling me. What I don't quite understand is how all my other fish have remained so healthy. However, I know corys are super-sensitive and might react badly to a lower level of ammonia than other fish..
It may well be that at the time I was trying to keep these corys I was also being a bit lazy with water changes. If that is the case, then we have an explanation! I've only been really strict with weekly water changes more recently, I'm ashamed to admit
I'd still like to know if the dirty gravel could be a contributing factor, though. I've noticed that the two cherry barbs I've had for the longest seem to have lost their barbels. They don't seem bothered, although one of them also has rather torn fins which aren't rotting the way they would with fin-rot, but aren't growing back. I wonder if this could have something to do with the gravel...

It is possible for a aquariums bacteria levels to crash. Introduce large amounts of Nitrogen and then drastically reduce the Nitrogen inputs. Similar to the famous ecology example of the fox and rabbit populations being interdependent.

Some fish are more sensitive to ammonia then others. Cory barbels will fall off with ammonia present at some pretty low levels; varies by species.

I went 10+ years keeping fish before I was serious about water quality and changes. :) I have seen a lot of hurt and have seen many others do the same. Cleaning tanks frequently is definitely not the norm in the hobby.

It is possible for a aquariums bacteria levels to crash. Introduce large amounts of Nitrogen and then drastically reduce the Nitrogen inputs. Similar to the famous ecology example of the fox and rabbit populations being interdependent.

Some fish are more sensitive to ammonia then others. Cory barbels will fall off with ammonia present at some pretty low levels; varies by species.

I went 10+ years keeping fish before I was serious about water quality and changes. :) I have seen a lot of hurt and have seen many others do the same. Cleaning tanks frequently is definitely not the norm in the hobby.

Good to know I'm not the only one lol! I was about to say, you'd think with 7 years experience I would have learnt by now lol.